A major role for c-Myc in the proliferation of normal cells is attributed to its ability to promote progression through G(1) and into S phase of the cell cycle. The absolute requirement of c-Myc for ...cell cycle progression in human tumor cells has not been comprehensively addressed. In the present work, we used a lentiviral-based short hairpin RNA (shRNA) expression vector to stably reduce c-Myc expression in a large number of human tumor cell lines and in three different types of normal human cells. In all cases, cell proliferation was severely inhibited, with normal cells ultimately undergoing G(0)/G(1) growth arrest. In contrast, tumor cells demonstrated a much more variable cell cycle response with cells from several lines accumulating in S or G(2)/M phases. Moreover, in some tumor lines, the phase of cell cycle arrest caused by inhibition of c-Myc could be altered by depleting tumor suppressor protein p53 or its transcriptional target p21(CIP/WAF). Our data suggest that, as in the case of normal cells, c-Myc is essential for sustaining proliferation of human tumor cells. However its rate-limiting role in cell cycle control is variable and is reliant upon the status of other cell cycle regulators.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Late Mesozoic carbonatites of Central Asia are developed within the Central Asian Orogenic Belt and adjacent territories of the Siberian and North China platforms. In terms of their structural ...position, age, geochemical characteristics, and other parameters, they differ from other carbonatite occurrences of Central Asia and are distinguished as the Late Mesozoic carbonatite province in Central Asia. The province includes separate areas of carbonatite magmatism, the geological position of which is determined by the relation with Late Mesozoic rift zones of intracontinental Asia. The carbonatites were formed within a relatively narrow time range (between 150 and 118 Ma) at the early evolution stages of these zones. The carbonatite-bearing complexes of the province are represented by subolcanic and volcanic associations of silicate rocks, carbonatites, magmatic non-silicate rocks (phosphates, sulfates, and others), as well as products of hydrothermal activity. The carbonatites are characterized by diverse composition and include calciocarbonatites, magnesiocarbonatites, and ferrocarbonatites. The silicate rocks are dominated by K–Na and K intermediate rocks. All these rocks have similar geochemical features determined by the elevated contents of LREE, Sr, Ba, and Pb, at low Nb and Ta contents. The typomorphic minerals of carbonatites of the province, in addition to carbonates, are fluorite, Ba and Sr sulfates or carbonates, LREE F-carbonates, and apatite. Unaltered carbonatites are enriched in
18
О and
13
С relative to mantle values, but in general fall within the compositional range of carbonatites around the world. Hydrothermal and supergene processes modified the mineral composition of carbonatites, which was accompanied by a change of the initial Sr, O, and C isotope composition. The Sr and Nd isotope composition of rocks of carbonatite complexes of the province in general depends on the age of the basement of a definite volcanic area. Carbonatites and associated silicate rocks have close isotope characteristics, but carbonatites usually show relative enrichment in (
87
Sr) and depletion in radiogenic neodymium (
143
Nd). The formation of the Late Mesozoic carbonatite province is related to the activity of mantle plumes, which controlled the Late Mesozoic magmatism in Central Asia. The plumes obviously were accompanied by fluid flows enriched in СО
2
, F, and S. This caused the enrichment of lithospheric mantle in volatile components, as well as REE, Sr, Ba, and K, which were extracted by a fluid en route to the surface. Subsequent melting of metasomatized mantle produced parental melts of carbonate-bearing rock complexes.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Proteins of the NUDIX hydrolase (NUDT) superfamily that cleave organic pyrophosphates are found in all classes of organisms, from archaea and bacteria to higher eukaryotes. In mammals, NUDTs exhibit ...a wide range of functions and are characterized by different substrate specificity and intracellular localization. They control the concentration of various metabolites in the cell, including key regulatory molecules such as nicotinamide adenine dinucleotide (NAD), ADP-ribose, and their derivatives. In this review, we discuss the role of NUDT proteins in the metabolism of NAD and ADP-ribose in human and animal cells.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Sn-rich islands with faceted Si pedestals were grown by MBE technique on VLS mechanism.•Sn island arrays were used as catalysts for the formation of Sn-rich islands.•A Sn-rich islands demonstrated ...the intense photoluminescence in the near-IR range.
The Sn-rich islands with a Si pedestal on the Si(1 0 0) substrate were obtained by the molecular-beam epitaxy technique. Initially, Sn films of different thicknesses were formed on the Si surface and then annealed to create the Sn island arrays, which were used as nanoobject growth catalysts. The Sn island density reaches up to 6 × 109 cm−2, whereas the Sn island sizes are changed in the range of 40–180 nm. The Sn-rich islands with the Si pedestal were first appeared after the Si deposition on the surface with the Sn islands in the temperature range of 300–450 °C. The new obtained nanostructures have the island density up to 4 × 108 cm−2 and the island sizes, which varied from 60 to 400 nm. The island growth with the pedestal occurred on the vapor-liquid-solid mechanism. The chemical analysis of the samples carried out using the energy-dispersive X-ray spectroscopy indicated the presence of the Sn-rich region on the top of nanoobjects. The intense photoluminescence from the Sn-rich islands with the Si pedestal was detected. The photoluminescence peak takes place at 1.55 µm.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Nicotinamide adenine dinucleotide (NAD) and its phosphorylated form NADP are the major coenzymes in the redox reactions of various essential metabolic pathways. NAD
+
also serves as a substrate for ...several families of regulatory proteins, such as protein deacetylases (sirtuins), ADP-ribosyltransferases, and poly(ADP-ribose) polymerases, that control vital cell processes including gene expression, DNA repair, apoptosis, mitochondrial biogenesis, unfolded protein response, and many others. NAD
+
is also a precursor for calcium-mobilizing secondary messengers. Proper regulation of these NAD-dependent metabolic and signaling pathways depends on how efficiently cells can maintain their NAD levels. Generally, mammalian cells regulate their NAD supply through biosynthesis from the precursors delivered with the diet: nicotinamide and nicotinic acid (vitamin B3), as well as nicotinamide riboside and nicotinic acid riboside. Administration of NAD precursors has been demonstrated to restore NAD levels in tissues (i.e., to produce beneficial therapeutic effects) in preclinical models of various diseases, such as neurodegenerative disorders, obesity, diabetes, and metabolic syndrome.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Phosphates of Ca8ZnLn(PO4)7 (Ln3+ = La – Nd, Sm – Lu) with β-Ca3(PO4)2-type structure were prepared by high-temperature solid-state technique on air. All compounds of Ca8ZnLn(PO4)7 are ...centrosymmetric and have R3¯c space group, which has been proved by several methods such as second-harmonic generation, dielectric spectroscopy, and Rietveld analysis. The influence of Ln3+ on the structure, luminescent properties and temperature of phase transitions, which corresponds with “tetrad” effect, has been investigated. The bandgap width and location of 4f Ln3+ and Ln2+ levels relatively to the energy bands were determined using the data of luminescent spectroscopy.
•Space group of Ca8ZnLn(PO4)7 compounds as centrosymmetric R3¯c and Zn2+ ions occupy only M5 position according to SXRD refinement.•The distribution of Ln3+ between M1 and М3 positions depends on the ionic radius of Ln3+.•Temperatures of first-order reversible phase transitions correspond with the “tetrad” effect.•The energies of excitons creation and bandgap were determined as Eex = 7.94 eV and Eg = 8.57 eV, respectively.•A scheme, which determines the location of Ln3+ and Ln2+ 4 f and 5d levels relatively to the energy bands was developed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Different types of commercially available stainless steels, Ni-based alloys as well as titanium and tantalum were evaluated as possible metallic bipolar plates and construction materials. The ...corrosion resistance was measured under simulated conditions corresponding to the conditions in high temperature proton exchange membrane (PEM) steam electrolysers. Steady-state voltammetry was used in combination with scanning electron microscopy and energy-dispersive X-ray spectroscopy to evaluate the stability of the mentioned materials. It was found that stainless steels were the least resistant to corrosion under strong anodic polarisation. Among alloys, Ni-based showed the highest corrosion resistance in the simulated PEM electrolyser medium. In particular, Inconel
® 625 was the most promising among the tested corrosion-resistant alloys for the anodic compartment in high temperature steam electrolysis. Tantalum showed outstanding resistance to corrosion in selected media. On the contrary, passivation of titanium was weak, and the highest rate of corrosion among all tested materials was observed for titanium at 120
°C.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
Identification of the Late Mesozoic carbonatite province in Central Asia is herein discussed. Its regional extent and distribution is investigated, and the areas with manifestations of carbonatite ...magmatism are described. It is shown that they were developed in terranes with heterogeneous and heterochronous basements: Siberian (Aldan Shield) and North China cratons; Early Paleozoic (Caledonian) and Middle–Late Paleozoic (Hercynian) structures of the Central Asian fold belt (Transbaikal and Tuva zones in Russia; Mongolia). Irrespective of the structural position, the carbonatites were generated within a relatively narrow time interval (150–118 Ma). The geochemical (Sr, LREE, Ba, F and P) specialization of carbonatites of the province is reflected in their mineral composition. Some rocks of the carbonatite complexes always include one or more distinctive minerals: fluorite, Ba–Sr sulfates, Ba–Sr–Ca carbonates, LREE fluorocarbonates, or apatite. Compared to counterparts from other age groups (for example, Maimecha–Kotui group in North Asia), these carbonatites are depleted in Ti, Nb, Ta, Zr and Hf. It is shown that the Sr and Nd isotope composition of carbonatites correlates with the geological age of the host crust. Rocks of carbonatite complexes associated with cratons are characterized by the lowest εNd(T) and highest ISr(T) values, indicating that their formation involved an ancient lithospheric material. Carbonatite magmatism occurred simultaneously with the largest plateau basalts 130–120 Ma ago in rift zones in the Late Mesozoic intraplate volcanic province of Central Asia. This interval corresponds to timing of global activation of intraplate magmatism processes, suggesting a link of the carbonatite province with these processes. It is shown that fields with the carbonatite magmatism were controlled by small mantle plumes (“hot fingers”) responsible for the Central Asian mantle plume events.
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•Late Mesozoic carbonatite fields occur on blocks with different crustal basement.•Carbonatites have the same geochemical specialization: high Sr, Ba, F, LREE and low Nb.•Fluid flows over mantle plumes caused of carbonatite formation
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It has been shown that methane can be formed in high amounts by co-electrolysis of CO2 and H2O using a nickel cathode, a CsH2PO4-SiC composite electrolyte and an IrO2 anode. The experimental ...conditions were 300 °C and 8 bar. The maximum efficiency close to 100% for methane was obtained at a current density of 10-15 mA cm−2. A small amount of hydrogen was formed as the only other product.
A distal fragment of the wing metacarpal of a pterosaur from the Upper Cretaceous (Campanian) deposits of the Orenburg Oblast has been identified as Azhdarchidae indet
.
based on the following ...combination of characters: absence of a large pneumatic foramen on the posterior side proximal to the ventral condyle; an asymmetrical groove between the condyles, a ridge on the ventral side of the ventral condyle, and a significant posterior bend of the distal epiphysis and adjacent part of the diaphysis. This is the first pterosaur recorded from the Late Cretaceous of the Southern Urals.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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